But in an absolute pinch, certain ways of addressing your cover letter are more off-putting than others.

Some of the worst ways to address a cover letter include"Dear HR professional" and a simple "Hi!"

Dear Reader,

We know it's frustrating when a job posting doesn't include the name of the person in charge of the hiring process.

We also know that's not an excuse to slap any salutation on your cover letter and send your application off.

According to Amanda Augustine, career advice expert for TopResume, you should always do some research to figure out who exactly the person reading your letter will be.

You can even play it safe by writing at the beginning of your cover letter: "I noticed you're working in [whatever department] at [whatever company]," so you show that based on your research, it looks like they're involved in the hiring process.

In the case that you absolutely, positively can't find a person's name, Augustine said certain ways of addressing your cover letter are more off-putting than others.

For example, "Dear Hiring Manager" and "Dear Recruiter" aren't great openings, but they're the best of many bad options.

Here's the full list of cover-letter openings, ranked in reverse order of egregiousness.

Sincerely, Business Insider staff

P.S. This advice doesn't apply in the case of an anonymous job posting, when a company is deliberately keeping their name and the names of their employees confidential.

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5. 'Dear Hiring Manager' or 'Dear Recruiter'

Justin Sullivan/Getty Images

The language in your cover letter should be at once professional and conversational, Augustine said. And these openings aren't overly formal or casual, which is a plus.

But the lack of customization — you could submit this letter to any company you're applying to — will still stand out.

1. 'To Whom It May Concern'

"It's so incredibly formal in its language," Augustine said of this opening. "I read that and I think, 'This person doesn't care at all.'"

If they did care, they would have tried to figure out who exactly the recruiter or the hiring manager is.

Moreover, "To Whom It May Concern" conveys exactly the opposite impression of professional and conversational that you're trying to project.

Augustine's rule of thumb when writing cover letters is to ask yourself: If this letter was coming to me, would I want to read it? Chances are good that, if someone addressed you this way, you wouldn't be so intrigued.